(a) Field of the Invention
The present invention relates to a nonaqueous stripper composition for negative chemically amplified resists which shows excellent removing capabilities, has anticorrosive effects on varieties of metallic substrate plates such as Al, W, TiN, WSi, SiON, SiNx, HTO, etc., improves productivity since it can be recycled as a nonaqueous stripper even after many applications, and is suitable in electronic material fields in which high precision processing is required, such as in the negative chemically amplified resist removing process which is recently noticed as resist pattern miniaturization is increasing in the manufacturing process of semiconductor components such as Integrated Circuit, Large Scale Integration, Very Large Scale Integration, etc.
(b) Description of the Related Art
Semiconductor components such as Integrated Circuit, Large Scale Integration, Very Large Scale Integration, etc. have been manufactured with lithography technology using a photoetching method. According to this photoetching method, semiconductor components are obtained by the process comprising forming a photoresist layer on an inorganic material substrate such as silicone wafer, etc. by a spin-coating method, exposing to light through a mask having desirable patterns thereon, forming a resist pattern by proceeding with the development treatment, carrying out an etching treatment or a diffusion treatment on the photoresist layer thereby exposing parts of the inorganic material substrate with this resist pattern being used as a mask, and delaminating and removing the used resist pattern from the inorganic material substrate using a stripper.
Varieties of organic or inorganic based strippers have been developed and used in the resist delamination. An organic based stripper comprising a main constituent of organic sulfonic acid is disclosed in Japanese Patent Laid-open Publication No. Showa 51-72503, and an organic stripper comprising a main constituent of alkylene glycol is disclosed in Japanese Patent Laid-open Publication No. Showa 43-7695. Furthermore, there are the piranha rinsing method using a mixture of nitric acid and hydrogen peroxide, and the RCA rinsing method combining ammonia and hydrogen peroxide, hydrochloric acid and hydrogen peroxide, and hydrofluoric acid, etc. as an inorganic based stripper.
However, technologies to stably perform 0.5 or less xcexcm microprocessing have recently been required as the resist pattern micronization is proceeding with the recent high integration of semiconductor component circuits. Therefore, 0.5 or less xcexcm pattern forming technologies have been required even in the currently produced photoresists, thus lithography technologies using radioactive rays having shorter wavelengths are being reviewed. As these radioactive rays discussed are ultraviolet rays represented as an I line having a wavelength of 365 nm, far ultraviolet rays represented as a KrF excimer having a wavelength of 248 nm and an ArF excimer having a wavelength of 193 nm, X rays represented as synchrotron radioactive rays, electron beam charge corpuscular beams represented as electron beams, etc., and varieties of resists are being suggested to cope with these radioactive rays.
Among these noticed is a resist using a reaction causing solubility changes in a developer by catalysis of acids which are produced by radioactive ray irradiation. These are normally called xe2x80x9cchemically amplified resistsxe2x80x9d which are divided into a negative type resist and a positive type resist. Particularly, it has been found that a negative type, resist has superior sensitivity, heat resistance, and adhesion to a substrate, and comprises an alkaline soluble binder resin, a cross link agent, an acid generating agent, and a solvent as main constituents. Binder resins become insoluble since acids are generated at areas irradiated by light exposing, and these acids activate a cross-linking agent in these resists. Thereafter, a negative type resist pattern can be materialized by carrying out the development. This materialized pattern is removed through the stripping process as the final step of the lithography process.
However, a negative type resist is difficult to delaminate and remove in the stripping process compared to a positive type resist. So, strong delaminating capabilities have been required in stripping a negative type resist, thus inorganic based strippers have been mainly used. In addition, the inconvenience exists that careful attention should be required in handling these inorganic strippers due to a bad influence on safety of workers as well as increases in the danger of fire when sulfuric acid, nitric acid, oleum, a mixture of nitric acid and hydrogen peroxide, etc. are heated to a high temperature of 120xc2x0 C. or more before used. Furthermore, they have been economically ineffective since water based inorganic strippers should all be disposed of after use due to the incapability of recycling, unlike a non-aqueous composition of the present invention. Due to these problems, non-aqueous organic strippers are recently becoming more widely used, and varieties of strippers are being suggested.
For example, a mixed solution of alkylbenzenesulfonic acid and a non-halogenized aromatic hydrocarbon based solvent is disclosed in Japanese Patent Laid-open Publication No. Showa 51-72503, a mixed solution of alkylarylsulfonic acid, aqueous aromatic group sulfonic acid, and a non-halogenized aromatic hydrocarbon based solvent is disclosed in U.S. Pat. No. 4,165,294, and a stripper in which polar or non polar organic solvent is added to organic sulfonic acid and 1,2-dihydroxybenzene is disclosed in European Patent Laid-open Publication No. 0119337. However, these strippers have low anticorrosive effects on varieties of metallic substrate plates such as Al, W, TiN, WSi, SiON, SiNx, HTO, etc., thus they are not practical in the applications.
It is an object of the present invention to provide a non-aqueous organic stripper composition for negative chemically amplified resists which has superior resist removal and delamination capabilities, anticorrosive effects on varieties of metallic substrate plates such as Al, W, TiN, WSi, SiON, SiNx, HTO, etc., recyclability as a non-aqueous stripper even after many uses, and can stably carry out 0.5 xcexcm or less microprocessing taking into account problems of the conventional technologies.
In order to accomplish the objects, the present invention provides a stripper composition for negative chemically amplified resists comprising:
a) 20 to 35 weight % of straight chained alkylbenzenesulfonic acids represented as in the following Chemical Formula 1: 
where R is an alkyl group having 10 to 14 carbons;
b) 10 to 34 weight % of light aromatic naphtha solvent;
c) 30 to 45 weight % of an organic compounds containing chlorine;
d) 15 to 25 weight % of hydroxybenzenes; and
e) 0.5 to 5 weight % of polyoxyethylene octylphenylether derivatives.
An alkylbenzenesulfonic acid represented as in the Chemical Formula 1 of a) is preferably decylbenzenesulfonic acid or dodecylbenzenesulfonic acid.
Furthermore, the organic compounds containing chlorine of c) are preferably one or more compounds selected from the group consisting of 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, and 1,3,5-trichlorobenzene.
Furthermore, the hydroxybenzenes of d) are preferably one or more benzenes selected from the group consisting of hydroxybenzene, o-cresol, m-cresol, p-cresol, and xylenol.
Furthermore, the polyoxyethylene octylphenylether derivatives of e) are preferably one or more derivatives selected from condensates having 7 to 12 moles of ethylene oxide.
In the following detailed description, only the preferred embodiments of the invention have been shown and described, simply by way of illustration of the best mode contemplated by the inventor(s) of carrying out the invention. As will be realized, the invention is capable of modification in various obvious respects, all without departing from the invention. Accordingly, the description is to be regarded as illustrative in nature, and not restrictive.
The present invention is described in detail as follows.
The present invention could be completed by a composition consisting of straight shaped alkylbenzenesulfonic acid of which an alkyl group has from 10 to 14 carbons, light aromatic naphtha solvent, an organic compound containing chlorine, hydroxy benzenes, and a polyoxyethylene octylphenylether derivative in a certain ratio in order to obtain a non-aqueous organic stripper composition for negative chemically amplified resists having excellent delamination capabilities and low corrosion effects on varieties of metallic substrate plates.
In a composition of the present invention, an a) constituent used is alkylbenzenesulfonic acid represented as in the Chemical Formula 1 of which an alkyl group has a range of from 10 to 14 carbons, wherein anticorrosive effects on a metallic substrate are weak when the number of carbons is less than 10 and application is difficult due to precipitation when the number of carbons is more than 14. Detailed examples of alkyl groups include a decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, etc. Particularly, since straight chained soft type alkyl groups inhibit metal corrosion more than branched chained hard type alkyl groups, straight chained soft type alkyl groups should be selected to be used, and decyl group and dodecyl group are more preferable in this aspect.
Alkylbenzenesulfonic acid represented as in the Chemical Formula 1 can be obtained easily by the notified preparation method, for example by the sulfonation of alkylbenzene with sulfur trioxide, etc. Furthermore, there are no special limits in the positions of sulfonic acid groups, and any position of ortho, metha, or para is preferable with alkyl groups.
Alkylbenzenesulfonic acids of a) constituents can be used alone or with two or more acids combined, in a composition of the present invention.
Light aromatic naphtha solvent of the b) constituent is a light mineral oil obtained by petroleum distillation, and brand names such as Kokosol 100 and Kokosol 150 obtained from SK Corporation, Korea, etc. can be used in a composition of the present invention.
Organic compounds containing chlorine of the c) constituent include, for example, 1,2,3-trichlorobenzene, 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, o-dichlorobenzene, p-chlorotoluene, etc in a composition of the present invention. These organic compounds containing chlorine can be used alone or with two or more compounds combined.
Hydroxy benzenes are preferably mixed as the d) constituent in order to improve resist delaminating properties in a composition of the present invention. Hydroxy benzenes include, for example, hydroxy benzene, o-cresol, m-cresol, p-cresol, xylenol, etc. These hydroxy benzenes are used alone or with two or more benzenes combined.
Polyoxyethylene octylphenylether derivatives of the e) constituent are compounds in which 7 to 12 moles of ethylene oxide are condensated in a composition of the present invention. HLB (Hydrophile-Lipophile Balance) values of these derivatives are determined by the addition of a number of moles of ethylene oxide, and derivatives which are within the range of from 12 to 14 carbons have superior permeabilities into metallic substrates, thus making a stripper contact with a substrate easily. HLB is a ratio of hydrophilicity and lipophilicity which is represented as a value between 0 and 20.
Resists which are targets of an organic stripper composition of the present invention, such as negative type chemically amplified resists, can be treated at a temperature range of from 70 to 90xc2x0 C. for a short time of within 10 minutes while inorganic based strippers are used at a high temperature of 120xc2x0 C. or more. Deposition methods in which a resist coated substrate is generally digested by a stripper solution for a certain time include a spray method in which a stripper solution is sprayed using a sprayer, a puddle method in which a certain amount of solution is dropped from rotating track equipment, etc.
Furthermore, efficiencies can be raised by applying supersonic waves during the stripping process. Resist patterns can be completely removed and a high quality substrate can be obtained by rinsing with an appropriate rinse solution or directly washing with water after removing resists with a stripper.